The present invention relates generally to dermal, transdermal, mucosal or transmucosal ingredient delivery devices. Such devices are designed to deliver ingredients to the skin or exposed mucosa of a subject. The device is referred to “dermal” or “transdermal,” as a function of whether or not the ingredients are formulated in such a way as to remain on the user's skin and be active there, or pass through the skin. The same distinction applies with respect to “mucosal” or “transmucosal” devices, but with reference to an exposed mucosal layer.
The ingredients to be delivered may vary widely. They may be “drug” ingredients, oral care ingredients such as flavors, drugs, etc., or they could be cosmetic ingredients such as perfumes, creams or the like. The term “active” ingredient as used herein is intended to refer to the primary ingredient or ingredients to be delivered by the device, and is not intended to be used in its “FDA” sense as referring only to “drugs.”
Devices for transdermal or percutaneous drug delivery and devices are typically characterized by delivering an amount of a drug or other ingredients, e.g., nitroglycerin, estrogen, estradiol, corticoid, levonorgestrel, etc. to the patient's skin at a rate controlled by the device. In a transdermal or transmucosal device, the drug is delivered systemically to the intended site of treatment within the body. Although effective for their intended use, such controlled release devices have limited utility for providing the kind of treatment which requires maximum delivery of the drug or active ingredient for local skin conditions, for example, lesions or abnormal skin features such as corns, warts, calluses, bunions, actinic keratoses and hard hyperkeratotic skin as is often found on the face, arms, legs or feet.
U.S. Pat. No. 4,849,224 to Chang et al. discloses an ingredient delivery device comprising a backing layer which defines an ingredient containing reservoir covering a microporous membrane that is permeable to the ingredients contained in the reservoir. The microporous membrane is heat sealed to the backing layer in the area surrounding the perimeter of the reservoir. An adhesive layer is adhered to the backing layer in the area surrounding the mircoporous membrane. A release liner covering both the adhesive layer and the microporous membrane is heat sealed to the backing layer concentric to and outwardly from the heat seal between the microporous membrane and the backing layer. In a second embodiment, Chang '224 discloses a similar arrangement, but with a peel sealable inner liner which underlies the microporous membrane and portions of the backing film. It is the inner liner, rather than the release liner, which is then heat sealed to the backing layer with a peelable heat seal which is concentric with the heat seal between the microporous membrane and the backing layer. In this device, both the release liner and the inner liner must be removed prior to application of the device to a patient.
Chang et al. U.S. Pat. No. 4,983,395 discloses a device which is similar to the second embodiment of the Chang '224 patent, except that 1) the membrane layer underlies some or all of the backing layer, 2) the inner liner, membrane and backing layer are all sealed together at the perimeter of the reservoir, and 3) the inner liner is adhered by an adhesive layer to the release liner.
Other types of delivery devices such as medicated plasters have been used for corns, warts, calluses, etc. However, the amount of active ingredient that can be delivered by such plasters is limited by the dimensions of the plaster and solubility of the active ingredient in the plaster. Consequently, repetitive applications are required for effective treatment. It would be desirable to provide a device which would provide maximum delivery of dermatological ingredients for local skin conditions or therapeutic drugs for delivery to the bloodstream.